Far from an original game concept, but a good game! I like how it's all split into levels instead of one endless arcade venture switching those crystals, feels like it makes the pace a lot more nameable. Gives you a break between each trial. One thing I'd have liked to see: entire grouping of jewels disappearing, not just a line, when there are more of them together. For example, if you have a cube of four of one kind, and manage to make a line of three on one side, it'd feel more rewarding if the entire grouping dropped away. Also, the green and the blue colors feel like they have very similar nuances, would be nice with more contrast. Overall, it's catchy! Nice work!
-cd-